Your clinical presentation of sore throat, severe back pain followed by swelling of ankles and also bloating suggest few possibilities which include most probably some kidney infection like glomerulonephritis (sometimes it develops as a complication of sore throat because of some bacterial or viral infection) or other possibilities like deep vein thrombosis (may be because of long distance travel to Hawaii) or could be due to collection and trapping of fluid (fluid retention) in lower legs because of some dysfunction with organs like heart, liver, apart from kidney.

I would suggest you to visit a physician for physical examination and investigations. Further work-up can include checking your blood pressure, investigations like urinalysis, complete blood profile, throat swab, Antistreptolysin titres (ASO) to rule out the above possibilities.

Based on results of these tests we can narrow down the possibilities to a single diagnosis.